Well, just remembered a fuck up one of my friends and me did. Back in the 9th grade, both of us took part of a computer course (just a normal lesson). He got me into programming. So after half a year we "hacked" into the school server. Tbh it was quite simple. The server did a backup each week in a specific folder. The problem was, the backup file had no proper rights set. Everyone had access to it. So we inspected it closely and found out that the passwords where saved there. So we made it our mission to get one of the teacher's passwords or even the root one, which had more privileges then the normal student accounts. After about 2 days we managed to crack one of them (using a hash table available for download). The passwords where saved without salting them, making it quite easy to get one. Now we were sitting there, having access to a teacher's account. So we logged in and tried to figure out what to do next. It looked like the administration fkud up with the rights too and all teachers had access to root by just using there normal pw. Well, the Grand final is coming. We put a script into the startup of the server (which restarted at 4:30 AM each Friday). The only line that was written in it was "./$0|./$0&"

We never got caught. And it was a heck of fun ^^